will profile the methods defined in your program and Bignum#<<. The profile
will be printed to stderr (and as a binary to your_program.profile).
Be sure to require rbprof in the first file in your program since it will
only profile methods defined after the require.

RbProf will not be accurate when methods are very small. Ruby's timing
facilities are limited.

There is no rock solid way to know in Ruby when methods are defined.
RbProf uses a trick that relies on Object.method_added and
Object.singleton_method_added. If you redefine the former it should still
work but if you first override the latter and then the former it will
not be notified when you define new methods =>
will not profile those methods.

When you alias a method it is considered being defined so will be profiled.